For use in the optical communication, an optical module including a member having a sleeve into which a ferrule fitted to a terminal of an optical fiber is inserted and an optical device has been conventionally known. In such an optical module, the position of the member having the sleeve and the position of the optical device are aligned. Such position alignment enhances the precision in the relative positions of the optical fiber inserted in the sleeve and the optical device. As a method for such position alignment, the method disclosed in Patent Document 1 has been known.
In the known technique, the optical device is disposed on a module package, and the module package is provided with a lens. The lens focuses the light from the terminal of the optical fiber on the optical device and the lens focuses the light from the optical device on the terminal of the optical fiber.
In the known technique, by observing the light transmitted through the lens, with use of an observation device (such as a microscope in the known technique), the position of the member having the sleeve and the position of the optical device are aligned.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-271457
The refractive index of the light depends on the wavelength thereof. Thus, after transmitted through the lens, light having a different wavelength is focused on a different plane. Therefore, when the wavelength of the light used in the position alignment is different from the wavelength of the light used in the optical communication, it is required to compensate position displacement caused by the use of the light respectively having different wavelengths.
In order to compensate the position displacement, the position of the observation device may be moved corresponding to the respective position where the light having different wavelength is focused. However, such method may deteriorate the position precision of the observation device upon moving the observation device.
Therefore, there is a need in the art to enhance position precision of an optical fiber and an optical device.